THE number of pre-school children with wheezing disorders has doubled over the past 10
years, according to a study published today.
The rise in asthma and non-allergic breathing difficulties may be caused by changes in
diet or obsessive hygiene in the home, a team of researchers reports. But it has ruled out
increased exposure to traffic pollution.
The findings come days after doctors
reported that the incidence of nut allergy had doubled since the end of the 1980s.
Asthma has reached epidemic proportions in Britain. One in seven children - approximately
1.5 million - now has the disease. The reason why asthma and other auto-immune diseases
have increased over the past few decades is still a puzzle.
Some scientists have argued that the obsession with cleanliness is to blame. Babies and
children are no longer in contact with the germs needed to prime a healthy immune system.
Others argue that fitted carpets, double glazing and central heating increase exposure to
house dust mites.
Prof Mike Silverman, an expert in child health at Leicester University who carried out
the latest study, said the increase covered all types of wheeze - from insignificant
wheezing to severe asthma attacks. The findings, published in The Lancet, come from a
comparison of questionnaires sent to the parents of 1,650 children in 1990 with a similar
survey of 2,600 children in 1998. All the children were aged between one and five and
lived in Leicestershire.
Over the eight years there was a significant rise in all types of wheeze from 16 per
cent of children to 29 per cent. The number of asthmatic children rose from 11 per cent to
19 per cent, while the proportion of children admitted to hospital for wheezing increased
from six per cent to 10 per cent. There was also an increase in transient wheezing, a
condition that normally disappears by school age, from three per cent to five per cent.
The increase was not just linked to allergies. The incidence of viral wheeze, the
response to a virus infection, rose from nine per cent to 19 per cent. The rise in
respiratory problems could not be linked to household risk factors such as passive
smoking, gas cooking, pets or low parental education attainment because those factors
declined over the period, the team reports.
Prof Silverman said factors unrelated to allergies were to blame for the rise. But he
ruled out traffic pollution as a likely cause. Part of the increase could be due to a
greater awareness of wheezing and asthma. But other symptoms of asthma, such as coughing,
had not increased over the decade.
He said: "The increasing prevalence of viral asthma can't be explained by
allergies. There may be something more fundamental that has made airway diseases increase.
We suspect that there is something going on. It may be related to diet, or something
developmental in the lungs before and after birth, or it may be connected to the immune
system. But we do not think that it is linked to pollution."
Prof Silverman plans to follow up the children in the study to look at levels of atopy,
or allergy, and lung function. Dr Martyn Partridge, of the National Asthma Campaign, said:
"This interesting study is in line with studies with slightly older children in
Australia showing significant increases in the number of children with wheezing disorders
over a 10-year period.
"While atopy is a risk factor in the development of wheezing disorders, this study
suggests that atopy alone cannot explain the dramatic rise in the number of children
suffering from asthma and other wheezing disorders. Further research is clearly needed and
Government action necessary to ensure sufficient attention to this increasingly common
condition."
Donated blood can be scrubbed free of a range of diseases, such as HIV, by adding a
chemical and bathing the blood in a beam of light, a company reported yesterday. The
technique, developed by a Californian firm, Cerus, is undergoing clinical trials and could
be approved for use in America next year.
One chemical, psoralen, is designed to penetrate cells, viruses, bacteria and other
pathogens where it seeks out RNA and DNA. When bathed in ultraviolet light for three
minutes, the chemical forms a crosslink across the double helix of genetic material,
disabling it.
3
May 2001: Carpets are piled high with toxic pollutants
16
February 2001: A runny nose may stave off asthma
4
January 2001: [International] Experts prove link between pollution and damage to lungs
7
July 2000: Asthma cases double in 20 years
